This invention relates to controlling flow of fluids ma liquid or gas system and more particularly to a check valve for use in the unidirectional delivery of fluid liquid or fluid gas under pressure from a first location in a system to a second location in a system while substantially preventing fluid flow from the second location back to the first location.
Check valves are in widespread use for permitting fluids to flow through a passage in one direction while preventing flow in the reverse direction. Most check valves employ a movable poppet urged by a spring to engage a valve seat, thereby closing the valve. When force is exerted against the face of the poppet by fluid in the system moving in the direction permitted by the check valve, and that pressure exceeds the force of the spring, the poppet moves away from the seat, opening the valve.
Check valves are used in a variety of applications. For example, one common application of a check valve is at a fitting on a storage tank, where the check valve permits a flow of fluid from an external location for delivery to the storage tank, and then assists with retaining fluid in the storage tank when the source of fluid pressure (such as a compressor) shuts off by closing to prevent fluid flow in the reverse direction.
Check valves can be exposed to severe environmental conditions, including large pressure fluctuations, temperature fluctuations, and turbulent flow. In some applications, check valves are subjected to frequent forward and reverse flow cycles. Consequently, the poppet and other internal parts of check valves are in many applications subject to substantial vibrations which can result in noise, damage, or failure. Some valves of the prior art include a guide, sometimes called a retaining piece, mounted inside the valve for guiding and limiting movement of the poppet to prevent damage. In valves known to the art, retaining pieces are frequently located so that installation and replacement is difficult, or are flexible in construction or otherwise ill-suited for the severity of the environment. Further, the inaccessibility of the internal parts of check valves known to the art generally necessitates replacement of the entire valve assembly when only one part of the valve, such as the spring, fails.
Further, check valves known to the art are often purpose-built for connection to specifically-sized or specifically configured pipes or conduits. This limits the usefulness and versatility of check valves known to the art, as such valves can only be used in connection with the configuration of pipe or conduit for which they are built. Still further, check valves known to the art require a variety of fabrication techniques to make the different parts that comprise the valve assembly. Parts like the poppet or guide are often molded or cast, while parts like the housing are often machined. The variety of fabrication techniques requires to make the parts of a check valve increases the cost of the valve assembly.
It would a decided advantage to provide an improved check valve that allows convenient replacement one or more parts internal to the valve, including, specifically the poppet, spring, and retaining piece. It would further be to decided advantage to provide an improved check valve that can be easily adapted by a user for use with conduits or pipes of various sizes or various configurations without requiring the purchase of an entire new valve assembly. It would further be a decided advantage to provide a check valve wherein most parts can be produced by efficient fabrication techniques, such as machining.